Field of the Invention
The present invention relates to robot controlling methods for controlling articulated robots, robot apparatuses, programs, recording media, and methods for manufacturing assembly components.
Description of the Related Art
Conventionally, various types of robot apparatuses are used in factories and so on, and nowadays, in order to carry out more complex operations than before, robot apparatuses that include multiaxial, articulated robots are widely used.
When an articulated robot is used as a production apparatus, the robot needs to operate at high speed in order to increase the work efficiency. Accordingly, it is necessary to determine, as soon as possible, that one motion has certainly completed, or in other words, that positioning has completed.
With respect to how the completion of positioning of a robot is to be determined, to date, a following technique has been proposed. For example, the position of the leading end of the robot is estimated on the basis of the position, the speed, and a torque instruction value of a servomotor, and if the estimated value falls within a range of permissible values of the leading end position set in advance, it is determined that positioning has completed (refer to Japanese Patent Laid-Open No. 3-257506).
However, according to the technique described in Japanese Patent Laid-Open No. 3-257506, the position of the leading end of the robot arm is estimated through a calculation on the basis of the value at an input side of a reduction gear, or in other words, on the basis of a detection angle detected by an encoder that detects the angle of rotation of a rotation shaft in a servomotor. In other words, what is detected is an angle at the input side of the reduction gear. The reduction gear that has low rigidity and is susceptible to vibration intervenes between the input side of the reduction gear and the leading end of the robot arm, and thus it is difficult to assure that the vibrations of the leading end have converged on the basis of the value at the input side of the reduction gear. Therefore, there is a case in which the vibrations of the leading end of the robot arm have actually not converged, and the precision of assembly work deteriorates in some cases.
In the meantime, it may be possible to simply stop a robot arm for a predetermined period of time before the robot arm moves to a subsequent motion, as described as a conventional technique in Japanese Patent Laid-Open No. 3-257506, but a stopping duration needs to be set with a considerable margin. Therefore, in a case in which the same assembly operation is carried out repeatedly, the excess time (margin) accumulates, and the work efficiency of the robot arm decreases.
The present invention is directed to increasing the work efficiency of an articulated robot by reducing an excess stopping duration.